sw_lw_sfp
DESCRIPTION
sftpTRANSCRIPT
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Created by: Imre Baumli 2010, IBM Advanced Tech.
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What is the difference What is the difference
between the SW and LWbetween the SW and LW
laserlaser transceiverstransceivers
This document describes a operation condition of a semiconductor lasers,
type of the semiconductor lasers, layer structure of the laser devices, operation
wavelength of a device, optical fiber terminologies, coupling losses, optical
transceivers PN coding and the difference between the SW-Short-wave and LW-
Long-wave laser optical transceivers.
In other words why the SW mini GBIC operating at =850 nm and why theLW mini GBIC at =1310 nm or =1550 nm.
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ContentContent
Operation condition of the semiconductor lasers
Type of the semiconductor lasers
Intensity modulation of the semiconductor lasers
Layer structure of the semiconductor lasers and the operation wavelength*
SW-Short-wave and LW-Long-wave operation range
Optical fiber (terminologies, classification, coupling light into core, losses)
What is the difference between the SW and LW mini GBICs?
SFP-Small Form-Factor Pluggable Part Number coding
Life time of laser diodes and laser safety classes
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The The operatioperationon conditioncondition ofof thethe semiconductorsemiconductor laserslasers
PPrinciplerinciple ofof thethe laserlaser operationoperation
R=99%R=99% R=97%R=97%
activeactive layerlayer
opticaloptical feedbackfeedbackOCOC mirrormirror
HRHR mirrormirror
pumpingpumping
laserlaser outputoutput
Light Amplification by Stimulated Light Amplification by Stimulated
Emission Of RadiationEmission Of Radiation
(Current injection)(Current injection)
During the oscillation process, the light is attenuated and amplifyed in the gain material
and the light beams with same wavelength are coupled out on the OC mirror. The
output of a laser is a coherent electromagnetic field.
where, HR = high reflection mirror, OC= output coupler mirror (semitransparent
mirrors)
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The The principleprinciple ofof thethe stimulatedstimulated emissionemission
hhff
hhff
EiEi
EkEk
NiNi
NkNk
hh=E=E22 --EE11hh=E=E22 --EE11
First the electron is on the higher level and the effect of the incoming stimulating photon will be that the
electron will be emit a clone (a new photon) which will be exactly same with the incoming photon in module,
in polarization and in the phase.
For the laser operation are necessary the following conditions:For the laser operation are necessary the following conditions:
1. Active layer (gain material) which working on the base of the stimulated emission.
2. Pumping power which change the material to active state with population inversion*
3. Optical feedback which usually is created with Fabry-Perot resonator* with (optical resonators)
The function of the resonator is the creation of the high optical energy density and the
hard frequency-selective dealing namely the assurance high spectral purity.
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Type of the semiconductor lasersType of the semiconductor lasers
OpticalOptical
OutputOutput
PowerPower
WavelengthWavelength
Spectral widthSpectral width
FabryFabry--Perot Perot
laserslasers
VCSEL VCSEL Vertical Cavity Surface Vertical Cavity Surface
Emitting lasersEmitting lasers
DFBDFB--Distributed Distributed
Feedback lasersFeedback lasers
= 850 nm= 850 nm=0,85 nm=0,85 nm
= 1300 = 1300 --1310 nm1310 nm= 2= 2--2,75 nm2,75 nm
= 1550 nm= 1550 nm=0,08 nm=0,08 nm
First optical
window
Second optical
window
Third optical
window
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=30=30--40 40 nmnm spectralspectral widthwidth
=0.=0.0088--44 nmnm
LasersLasers
LEDsLEDs
0.5xPmax0.5xPmax
0.5xPmax0.5xPmax
PP
ff
cc
f
c
df
d
df
d
f
c
cf
cf
22
1
!!!
=
=
=
=
=
fc
= 2
ff relationship from relationship from nmnm-- to to HzHz..
SpectralSpectral widthwidth ofof LEDsLEDs andand laserslasers
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VCSELVCSEL Vertical Cavity Surface Emitting lasers:
They are the type of the semiconductor lasers with a monolithic laser resonator, where the emitted light leaves
the device in a direction perpendicular to the chip surface.
The resonator (cavity) is realized with two semiconductor Brag mirrors and between these mirrors is an active
region (gain structure). The active region is electrically pumped with circa 50 mW (tens of milliwatts)
and generated an output power in the range 0,2 5 mW . The current is applied through a ring electrode.
FabryFabry--PeroPerott lasers:
A laser oscillator in which two mirrors are separated by a amplifying medium (gain) with an inverted
population, making Fabry-Perot cavity. Standard diode lasers are Fabry-Perot lasers.
Exist two resonator type: with plan-parallel (R1, R2 = ) and with spherical mirrors (R1, R2 = L/2)The thickness of active layer at heterojunction lasers, strip lasers (mirror separation distance) is usually
d < 1 m or d= 0,2 m.
DFBDFB Distributed Feedback lasers :
Are the type of the laser devices where operating with very small spectral width in the third optical window
and the active layer of the device has integrated a diffraction grating which can be different special form
(normal trapezoidal, rectangular, sinusoidal, ...etc)
Where: ngng - is the group refractive index, BB - is the Bragg wavelength and mm is a integer number
For For m=1m=1 the grating is called firstfirst--order gratorder grating. ing.
The DFB lasers are characterised by The DFB lasers are characterised by very clean spectral linevery clean spectral line widthwidth..
This type is used in the This type is used in the high speed optical communicationhigh speed optical communication and in the cable TV applications.and in the cable TV applications.
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Intensity modulation of the semiconductor lasersIntensity modulation of the semiconductor lasers
In practice for the semiconductor lasers usually it is used the intensity modulation
Necessary power for the modulation is created by a driver circuit
The key parameter of the modulation is the modulation index (modulation deep)
minmax
minmax
PP
PPm
+
=
p
Popt
t
Pmax
Pmin
Pop
Popt
t
Po
Pmax
Pmin
The modulation index variation during digital and sinusoidal modulation
The main parameter of the light source is the outgoing optical power
What is the intensity modulation?
If the current of the device (laser diode) containing a modulation term, in this case the modulator current
will be change the outgoing optical power of the device.
In the intensity modulation it is required that the device to be modulated at high frequency, which is perfect for
the semiconductor lasers.
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Usually the device is modulated at third part of Usually the device is modulated at third part of
the the relaxation resonance frequencyrelaxation resonance frequency FFMM=(1/3)f=(1/3)fRR
The maximal value of the The maximal value of the relaxation resonancerelaxation resonance
frequencyfrequency today is today is 10 10 GhzGhz..II
ith
Popt
iii
PxPx
The other very important is, that the device must be modulated on the linear part of the
characteristic (after the ith - threshold current).
During the optical transfer (communication), the device is not powered down completely
(totally), only until the threshold current.
The modulation process is characterized by chirp because during the variation of the
optical power, is change the value of the laser frequency.
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Layer structure of the semiconductor lasersLayer structure of the semiconductor lasers
light light
emissionemission
Lower Lower
BraggBragg
reflectorreflector
activeactive
layerlayer
UpperUpper
BraggBragg
reflectorreflector
The total The total tichnesstichness of the of the
active layeractive layer is usually few is usually few
micrometer.micrometer.
The mirror separation distance The mirror separation distance
is usually is usually L < 1 cmL < 1 cm..
HR = HR = high reflection mirrorhigh reflection mirror
OC = OC = output coupler mirroroutput coupler mirror
R1=L/2R1=L/2 R2=L/2R2=L/2
Spherical resonatorSpherical resonator
amplifyingamplifying
mediummedium
R1=R1= R2=R2=
PlanePlane--parallel resonatorparallel resonator
amplifyingamplifying
mediummedium
LL
HRHR
mirrormirror
OCOC
mirror
HRHR OCOC
Uniform grating DFB laserUniform grating DFB laser
The The grating periodgrating period (():):
========mmBB/2/2nnggFor For 1,5 1,5 m m InGaAsPInGaAsP laser,withlaser,withfirst order grating the typical value first order grating the typical value
of of ngng=3,4=3,4
and and ========0,23 0,23 mm
Are used usually at Are used usually at 40km/2Gb40km/2Gb
or or 10km/4Gb10km/4Gb optical transfers.optical transfers.
GaInAsPGaInAsP
GaInAsP waveguide layer
n-InP buffer layer
n-InP substrat
n-InP buffer layer
For laser operation it is necessary for:
- active layer (which working after stimulated emission)
- population inversion (pumping)
- optical resonator (for light wave amplification)
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g1
g2
((g1=1, g2=1)g1=1, g2=1)
planeplane--parallelparallel
g1=g1=--1, g2=1, g2=--11
sphericalspherical
Stability of the FP resonators:Stability of the FP resonators:
They must be They must be fullfillfullfill the stability criteria:the stability criteria:
0< g10< g1g2 g2
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TransferTransfer characteristiccharacteristic ofof FP FP resonatorresonator
TPF=I/I0
dB
f (Hz)
R=0.75
R=0.90
R=0.99
-15
-25
-40
-1 0 +1
FSR=FSR=f=c f=c //2d2d FreeFree SpectralSpectral RangeRange
FWHM=FWHM=ff
IImaxmax--IIminmin
IImaxmax--IIminmin //22
)2
sin(1
2(
2
0
1
1
n
f
R
RII
TFP
+
==
((AiryAiry transfertransfer functionfunction ofof filter)filter)
Between the mirrors the material is air with Between the mirrors the material is air with n=1n=1, we have , we have
((TheoreticalTheoretical AiryAiry transfertransfer functionfunction))
)2sin(1
2(
2
0
1
1
+
==
fR
RII
TFP
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GaGaxxInIn11--xxAsAsyyPP11--yyactive layeractive layer
(d=0,2 (d=0,2 m)m)p p InPInP subsratsubsrat, 2 , 2 mm
SiO2metal metal
contactcontact
metal metal
contactcontact
p p GaInAsPGaInAsP subsratsubsrat
n n InPInP subsratsubsrat, 1 , 1 mm
n n GaInAsPGaInAsP subsratsubsrat
GaAsGaAs oror
GaGaxxAlAl11--xxAsAsactive layeractive layer
(d=0,2 (d=0,2 m)m)p p GaAlAsGaAlAs subsratsubsrat, 2 , 2
mm
SiO2metal metal
contactcontact
metal metal
contactcontact
p p GaAsGaAs subsratsubsrat
n n GaAlAsGaAlAs subsratsubsrat, 1 , 1
mm
n n GaAsGaAs subsratsubsrat
Double Double heretojunctionheretojunction structurestructure
d=0,2 d=0,2 mm
lossloss
amplificationamplification
losslossOptical powerOptical power
distribution
Refractive Refractive
index index
variationvariation
Temperature variation
of the threshold current: IIthrthr=I=Ithrthr(0)(0)expexp(T/T0)(T/T0)
The threshold current for 0 Kelvin is (for DH lasers, I(T)=0 if T=0 K):
where: L is the mirror distance, d- diffusion thickness, - attenuation,i internal quantum efficiency, nGaAs = 3,6 refractive index , -confinement factor and r1=r2= r =(nGaAs nair/nGaAs
+nair)2 = 0,32 are the reflection coefficients
)(1
ln2
118)0(
21
2TI
L
dqf
rrI outin
i
thr+
+
+
=
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Layer structure of SW and LW laser diodes and the operation wavelength
The The latticelattice constantconstant andand thethe energyenergy bandband gapgap forfor differentdifferent materialsmaterials
aa00(GaAs) = 5.6533 (GaAs) = 5.6533 AAaa00(InP) = 5.8688 (InP) = 5.8688 AAaa00(GaP) = 5.4512 (GaP) = 5.4512 AAaa00(InAs) = 5.0584 (InAs) = 5.0584 AAaa00(AlAs) = 5.6605 (AlAs) = 5.6605 AAaa00(GaSb) = 6.10 (GaSb) = 6.10 AA
1 angstrom=101 angstrom=10--88 cmcm
GaPGaP
6.106.10 6.156.155.6533 5.6533 5.4512 5.4512 5.86885.8688
6.0584 6.0584 5.66055.6605
F
o
r
b
i
d
d
e
n
F
o
r
b
i
d
d
e
n
b
a
n
d
b
a
n
d
E
g
E
g
(
e
V
)
(
e
V
)
LatticeLattice constantconstant aa00 ( ( AA--angstromangstrom))
InPInP
InAsInAs
GaAsGaAs
AlAsAlAs
AlSbAlSb
GaSbGaSb
2.32.3
0.40.4
1.41.4
1.31.3
2.22.2
1.651.65
0.70.7
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GaGaxxAlAl 11--xxAsAsactive layeractive layer
GaGayyAlAl 11--yyAsAs
GaGayyAlAl 11--yyAsAsSW laser device layer structure First optical window range:
= 820 nm 880 nm
The active layer GaGaxxAlAl11--xAsxAs which is doped in x % in Al-aluminium, is lattice matched
to GaGayyAlAl11--yyAsAs layer which is doped in y >>>> x % in Al. The percent of the aluminium content will be modify theEg of the thernary and will be modify the wavelengthwavelength ofof thethe emittedemitted radiationradiation..
The properties of the semiconductor compoud can be described by Vegards law:
a(Gaa(GaxxAlAl11--xxAs) = As) = xxa(AlAsa(AlAs) ) (1(1--x)x)a(GaAs),a(GaAs), where a - is the lattice constant.
The lattice constant and energy band gap value of the materials resulting from the graphic.
5,6605x + 5,6533 5,6533x = 5,6605y + 5,6533 5,6533y0,0072x = 0,0072y x y (y >>>> x)
For the energy bandgap (forbidden band of thernary structure) we can apply same law:
Eg(GaEg(GaxxAlAl11--xxAs) = xAs) = xEg(AlAs) Eg(AlAs) (1(1--x)x)Eg(GaAsEg(GaAs)) Eg(x) = 2,2x +(1-x) 1,4 = 0,8 x +1,4
For 0,850 nm = 1.24/Eg for first optical window the forbidden band must be Eg = 1,24/0,850 = 1,45 eV1,45 = 0,8 x +1,4 x = 0,0625 Al % and y must be higher as xFrom the definition of the operation wavelength, resulting for the SW-short wave operation range:
====0,855 m = 855 nm which is the first optical window.][24,1
mEgEg
hc
h
EvEc
c
f
c ====
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2nd optical window: =1285 1330 nm
3rd optical window: =1525 1575 nm
GaGaxxInIn11--xxAsAsyyPP11--yyactive layeractive layer
LW laser device layer structureInP
InP
The active layer of the LW laser device is the material system - GaGaxxInIn11--xxAsAsyyPP11--yy - gallium indium
arsenide phosphide which is doped in x % in In indium and y % in P-phosphide.
This material system can be used for the realization of lasers in the spectral window around
1310 nm and 1550 nm which are the second and third optical windows.
The properties of this semiconductor compound (GaGaxxInIn 11--xxAsAsyyPP11--yy) ) can be described by
Vegards law.
a(Gaa(GaxxInIn11--xxAsAsyyPP11--yy ) = xy) = xya0(GaAs) + x(1a0(GaAs) + x(1--y)y)a0(GaP) + (1a0(GaP) + (1--x)yx)ya0(InAs) + (1a0(InAs) + (1--x)(1x)(1--y)y)a0(InP) a0(InP) = = == 5.65335.6533xy + 5.4505xxy + 5.4505x(1(1--y) + 6.0584(1y) + 6.0584(1--x)x)y + 5.8688(1y + 5.8688(1--x)x)(1(1--y)y)
Using this law and know the semiconductor compounds GaAs, GaP, InAs, and InP it is
possible to determine the coefficients x and y and the operation wavelength of the laser
device.
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a(Gaa(GaxxInIn11--xxAsyP1AsyP1--y ) = a0(x,y) =5.8688 y ) = a0(x,y) =5.8688 0.4176x + 0.1896y + 0.0125xy0.4176x + 0.1896y + 0.0125xy
The The materialmaterial shystemshystem GaGaxxInIn11--xxAsAsyyPP11--yy itit is is latticelattice matchedmatched toto InPInP layerlayer ((withwith latticelattice constantconstant
a(InPa(InP) =5,8688) =5,8688) :) :
5.8688 5.8688 0.4176x + 0.1896y + 0.0125xy = 5.8688 0.4176x + 0.1896y + 0.0125xy = 5.8688 0.4176x = 0.1896y + 0.0125xy0.4176x = 0.1896y + 0.0125xy
For the x % and y % of In and P resulting the following relationship:
0.100125.04176.0
1896.0
= yy
yx
x
xy
=0125.01896.0
4176.0
If y=1 y=1 resultingresulting x=0.468x=0.468, , butbut allwaysallways y y must be must be higherhigher asas x x ((y>xy>x))
Resulting x < 0,468 (the In-indium % of the active layer)
Egnm
24.11310 =
For 1310 nm
For 1550 nm
Egnm
24.11550 = eVEg 94.0
310.1
24.1==
eVEg 80.0550.1
24.1==
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Applying the Applying the VegardsVegards lawlaw for the energy band gap of the active layer for the energy band gap of the active layer resuktingresukting::
Eg(GaEg(GaxxInIn11--xxAsAsyyPP11--yy) = ) = xyxyEg(GaAsEg(GaAs) + x(1) + x(1--y)y)Eg(GaP) + (1Eg(GaP) + (1--x)yx)yEg(InAs) + (1Eg(InAs) + (1--x)(1x)(1--y)y)Eg(InP) =Eg(InP) =
= xy= xy1,4 + x(11,4 + x(1--y) y) 2,3 + (12,3 + (1--x) x) yy 0,4 + (10,4 + (1--x) x) (1(1--y) y) 1,3 =1.1,3 =1.3 + x 3 + x -- 0.9y0.9y
For Eg = 0,94 eV if x=0,36 (In %) resulting y=0,8 (P %) and resulting = 1310 nm
0,94 = 1.0,94 = 1.3 + 0,36 3 + 0,36 -- 0.9y0.9y y=0,8 =1.24/0,94 = =1.24/0,94 = 1310 1310 nmnm (2(2--nd nd opticaloptical windowwindow))
For Eg = 0,80 eV if x=0,46 (In-indium %) y=1,06 (P-phosphide %) and resulting = 1550 nm
0,80 = 1.= 1.3 + 0,46 3 + 0,46 -- 0.9y0.9y y=1,06 =1.24/0,80 = =1.24/0,80 = 1550 1550 nmnm (3(3--rd rd opticaloptical windowwindow))
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SW-Short Wave and LW-Long Wave operation range
TheseThese peakspeaks cancan be be attributableattributable toto
OH OH hydroxilhydroxil ion ion contentcontent ofof thethe glassglass
fibrefibre..
After 1800 nm the attenuation increase
dinamically and appears the nonlinear effects
namely the refraction index n=n(P) from the
core deppend on the optical power of the light.
-Raman scattering PRkszb=570mW
-Brillouin scattering, PBkszb=1mW
-FWM - Four wave mixing
Mix the frequences in 1.55m band and appears noises
[[[[[[[[dBdB]]]]]]]]
[[[[[[[[nmnm]]]]]]]]850850 13101310 15501550 18001800400400
11--2 dB2 dB
0.4 dB0.4 dB
0.10.1--0.2 dB0.2 dB
At At 1550 nm1550 nm we have the we have the
theoretical minimum optical loss theoretical minimum optical loss
for silicafor silica--based fibers (quartz) based fibers (quartz)
about 0,2 dB/km.about 0,2 dB/km.
3rd optical window
(SMF - SM fibre)
2nd optical window
(SMF - SM fibre)
1st optical window
(MM fibre)
1/4
(Reilay scattering)
LW Operation Range
Short bandShort band (1450(1450--1510)1510)
Long bandLong band (1570(1570--1625)1625)
Conventional bandConventional band (1525(1525--1560)1560)
SW Operation Range
PinPout=Po10-Loopticalptical powerpower lossloss
L=1kmL=1km
glassglass
fiberfiber
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Classification of optical fibers
1.1. AAfterfter the refractive index profilethe refractive index profile:: SI SI Step Index FibersStep Index Fibers
((GRINGRIN--GradedGraded Index Index FiberFiber))
-- One dimensionOne dimension paraparabolicbolic
-- Two dimension parabolicTwo dimension parabolic
2.2. AAfterfter the propagation modesthe propagation modes:: SM-Single Mode Fiber
MM Multi Mode Fiber
50/62.5 m 9 m
50 m
SW LW
3.3. AAfterfter dispersion characteristicdispersion characteristic::
DSFDSF-- DispersionDispersion ShiftedShifted FiberFiber D D ======== DwDw + + DmDm
NDSFNDSF-- NotNot DispersionDispersion ShiftedShifted FiberFiber
NZNZ DSFDSF-- NoNonn--ZZeroero DispersionDispersion ShiftedShifted FiberFiber
more index profilesmore index profiles (for (for DS DS fibersfibers)
Dispersion ======== waveguide dispersionwaveguide dispersion + + modal dispersionmodal dispersion
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Dispersion Shifted Fiber and Dispersion Flattened Fiber
Dispersion Shifted Fiber
- Increase waveguide dispersion at higher wavelengths
- This can be eliminate with various refractive index profiles and
the result is Dispersion Shifted Fiber.
Dispersion Flattened Fiber
- They are fibers with low dispersion over a range of wavelengths with
complex index profiles.
Dispersion Flattened Fiber index profiles
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Technical terminology of optical Technical terminology of optical fibersfibers
-- AttenuationAttenuation
NANA -- Numerical Aperture*Numerical Aperture*
-- Refractive Index DifferenceRefractive Index Difference
-- Maximum Time DifferenceMaximum Time Difference
DD Dispersion Dispersion
VV -- Normalized Frequency**Normalized Frequency**
M M Number of modesNumber of modes
RR Bend Radius* (R minim)Bend Radius* (R minim)
=c
L n 1
= = --1010lg(Pout/Pin)lg(Pout/Pin) [ dB/km][ dB/km]
NA = sinNA = sinkk = (n= (n1122 nn22
22 ))1/21/2
= (n= (n1122 nn22
22 ))/2n/2n1122
= 3
2
4)( ooS
D1200 nm 1200 nm 1160600 0 nmnm
--operating wavelengthoperating wavelength
NAaa
V nn ==
22 2
2
2
1
M M VV22/2/2 ][405,2
2nm
NAac
NAR acritic2
/=
CutCut--off wavelengthoff wavelength
(for Step Index fibers)
(for SMFs)
V = 2,405
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Coupling light into fiber
3
NumericalNumerical aapertureperture lossloss
FressnelFressnel reflectionreflection lossloss
nn22
nn11acceptanceacceptance conecone
NA=sinNA=sinkk
((numericalnumerical apertureaperture))
NA=(n12-n2
2)1/2
((halfhalf angleangle ofof
acceptance acceptance conconee))
n1>>>>n2
n2
SiOSiO22--corecore
claddingcladding
criticcritic
kk
1
2
n=1
50 50 mm
125 125 mm
Ray propagation in the Step Index fiberRay propagation in the Step Index fiber
Coupling light into fiberCoupling light into fiber
Source
Core
SW LD for MMF
LW LD for SMF
Psource core
max=arcsinNA
Pfiber
Laser Diode
f()
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core
AreaArea mismisssmatchmatch losslossSource
core
FressnelFressnel rreflectioneflection lossloss
Source
NumericalNumerical apertureaperture losslossSource
core
L = -10lg() [ dB]
The coupling efficiency:
sin2
max
2/
=== NAPsourcePfiber
The coupling loss in dB:The coupling loss in dB:
L=L=--1010lg(1lg(1--r)r) ======== 0,180,18 [[dBdB]]
rr== (n1(n1--n/n1+n)n/n1+n)22 == 0.04 0.04
(for glass/air: n(for glass/air: n ==1,5, n11,5, n1==1)1)
(Fresnell reflection coefficient)
aa
NAa
NAa
s
c
ss
cc =
2
The coupling loss in dB:L = -10lg(ac/as) [ dB]
LossesLosses atat lightlight couplingcoupling intointo a a fiberfiber
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Normalized Frequency and the cutNormalized Frequency and the cut--off wavelengthoff wavelength
NAaa
V nn ==
22 2
2
2
1NF value is: V ==== 2,405
Is the limit of the single mode operation.Is the limit of the single mode operation.
Base modes
HE11TMTM0101
TETE0101
HEHE1111 HHyybridbrid Electromagnetic ModesElectromagnetic Modes
TMTM0101 TransTransverseverse MagneticMagnetic ModesModes
TETE0101 TraTrannssverseverse Electric ModesElectric Modes
V
nn11--corecore
nn22--claddingcladding
nneffeff==KK
V=2.405V=2.405
Higher modesHigher modes
Single Mode Single Mode
operation rangeoperation range
2
2
mod
VN es
The number of modesThe number of modes
Multi Mode operation
range
We can eliminate the higher modes using inequality We can eliminate the higher modes using inequality V V 2,4052,405 a a 2,405/22,405/2NANA
for SMF-Single Mode Fibers a 9 m (for LW fibers) and for cut-off wavelength
2a2aNANA /2,405 ==== 1,306dNA [[[[nm]]]] (SMF small core diameter, and cut-off value > 1260)
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What is the difference between the SW and LW mini GBICs?
All mini GBIC has integrated a PIN photodiode and a laser transceiver
(optical transceiver)Laser transmitter (Laser transmitter (laserdiodelaserdiode))
VCSEL or FPVCSEL or FP--FabryFabry--Perot & DFB Perot & DFB
lasers lasers
Rise/Fall time*Rise/Fall time* trtr = 90 = 90 psps
mini
GBIC/SFP
Receiver (PIN photodiode)Receiver (PIN photodiode)
Rise/Fall time*Rise/Fall time* recrec = 50 = 50 psps
(where GBIC = Gigabit Interface Converter)
The rise/fall time values are the followings for the 4Gb/s SFP Small Form-Factore Pluggable devices:
for receiver 50 ps for transceiver 90 ps.
The FP laser transceivers are used usually for 2Gb/s or 4Gb/s up to 4 km optical reach and the DFB
laser transceivers are used from 4 Gb/s or 8 Gb/s from 10 km or higher link distance.
optical channeloptical channel
TXTX
RXRX
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How we can list the WWPN -Word Wide Port Number, location code and port speed of the the host adapters
in AIX environemnt in case of a DS8k storage?
vbb08c0 # lsrsrc -xt IBM.EssHAPort logicalName locationCode wwpn portSpeed
"cpssfc0233" "U1300.001.RJ69540-P1-C4-T3" "500507630813c6ac" "4 Gb/s"
"cpssfc0232" "U1300.001.RJ69540-P1-C4-T2" "50050763081386ac" "4 Gb/s"
"cpssfc0231" "U1300.001.RJ69540-P1-C4-T1" "50050763081346ac" "4 Gb/s"
"cpssfc0230" "U1300.001.RJ69540-P1-C4-T0" "50050763081306ac" "4 Gb/s"
"cpssfc0303" "U1300.001.RJ69575-P1-C1-T3" "500507630818c6ac" "4 Gb/s"
"cpssfc0302" "U1300.001.RJ69575-P1-C1-T2" "50050763081886ac" "4 Gb/s"
"cpssfc0301" "U1300.001.RJ69575-P1-C1-T1" "50050763081846ac" "4 Gb/s"
"cpssfc0300" "U1300.001.RJ69575-P1-C1-T0" "50050763081806ac" "4 Gb/s"
vbb08c0 #
Each host adapter is populated with 4 mini GBICs (SFPs).
vbb08c0 # lsdev -C|grep cpssfc023
cpssfc023 Available 02-02-03 IBM Yukon FC adapter
cpssfc0230 Available 02-02-03 IBM Yukon FC adapter
cpssfc0231 Available 02-02-03 IBM Yukon FC adapter
cpssfc0232 Available 02-02-03 IBM Yukon FC adapter
cpssfc0233 Available 02-02-03 IBM Yukon FC adapter
vbb08c0 #
T0
T1
T2
T3
Host adapter ports4 pieces pluggable
optical transceivers
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Summary
The difference lies in layer structure of the laser optical transceivers.
In case of the SW active layer structure from the Vegards law resulting different value for the
energy bad gap as for the LW quaternary structure, therefore the lamda will be different.
From the definition of the laser operation wavelength resulting different value for SW and for LW active layer
structure.
In first case [820 880] nm and in case of the LW active layer structure resulting [1285 1575] nm.In case of the thernary (three layer structure) resulting the following operation wavelength for the laser.
GaGaxxAlAl11--xxAsAsactive layer
dopped in X % Al-aliminium
GaGayyAlAl 11--yyAsAs
GaGayyAlAl 11--yyAsAsSW laser device layer structure
[820 880] nm
nmch
h
EEc
fc
vc
850AsAlGaEAsAlGa )()( X-1XgX-1X
=
==
(1st opt. window)
Emitted wavelength for SW active layer
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GaAs emit radiation at ==== 870 nm wavelegth. The 1st optical window is at ==== 850 nm.If the GaAs is dopped in X % in Al-aluminium, the Eg of the thernary GaGaxxAlAl11--xxAsAs will be change
which will be modify the wavelength of the emitted radiation. For the laser diodes which operating
in 1st optical window the active layer is GaGaxxAlAl11--xxAsAs (doped in X % in Al) which is lattice matched
to the GaGaYYAlAl11--YYAs As layer (dopped in Y % in Al, where Y > X).
If x > 0,37 resulting indirect transition structure
If x
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For the laser diodes which operating at 2nd or 3rd optical windows the active layer structure
is GaGaxxInIn11--xxAsAsyyPP11--yy which is lattice matched to the InP layer.
The active layer is dopped in X % in In-indium and in Y % in P phosphide.
For x < 0,47, y 2,2x resulting the direct transition structure.
The variation of X and Y will be change the value of Eg of the quaternary which will be modify
the wavelength of the emitted radiation between [1285 1575] nm.
[1285 1575] nm
GaGaxxInIn11--xxAsAsyyPP11--yyactive layer dopped in
X % in In-indium and Y % in P- phosphide with Y > X
LW laser device layer structure
InP
InP
In case of the quaternary (four layer structure) the operation wavelength of the
laser transceiver will resulting for second or third optical window.
nmP
ch
hPEE
cfc
YYvc
1550/1310AsInGaEAsInGa )()( 1YX-1Xg1YX-1X
=
==
Emitted wavelength for LW active layer
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FINISAR Part FINISAR Part NumberNumber codingcoding: F : F --TLFTLF -- 8585 -- 2828 -- PP-- 22 -- B B -- NN -- VV
F = FinisarF = Finisar
85 = 850 nm (1st optical window)
(VCSEL with PIN receiver)
13 = 1310 nm (2nd optical window)
FP Fabry Perot w PIN receiver
14 = 1310 nm (2nd optical window)
DFB- Distributed Feedback w PIN receiver
85 = 850 nm (1st optical window)
(VCSEL with PIN receiver)
13 = 1310 nm (2nd optical window)
FP Fabry Perot w PIN receiver
14 = 1310 nm (2nd optical window)
DFB- Distributed Feedback w PIN receiver
TRX-XFP TRX-XFP
24 = 2x, 4x FC (2, 4 Gb/s operation speed)
28 = 8x FC (8 Gb/s operation speed)24 = 2x, 4x FC (2, 4 Gb/s operation speed)
28 = 8x FC (8 Gb/s operation speed)
P = Pluggable (SFP)P = Pluggable (SFP)
1 = 1st generation , 2 = 2nd generation1 = 1st generation , 2 = 2nd generation
B = standard bail , W = wide bailB = standard bail , WW = wide bail
N = Extended Temperature (-5 to -20 C to + 85 C)
T = Industrial temperature (-40 to 85 C)
NN = Extended Temperature (-5 to -20 C to + 85 C)
TT = Industrial temperature (-40 to 85 C)
V = Standard reach w rate select
D = Reduced reach w rate selectVV = Standard reach w rate select
DD = Reduced reach w rate select
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SSW W AVAGOAVAGO Part Part NumberNumber codingcoding: : AFAFBRBR -- 5757 -- DD7A7A PPZZ
AFAF = = AvagoAvago Fiber OpticsFiber Optics
BRBR = multimode device= multimode device
5757 = SFP (a 59 would be SFF)= SFP (a 59 would be SFF)
DD = 8/4/2G (= 8/4/2G (RR would be 4/2/1G)would be 4/2/1G)
77 = Gen 2 (= Gen 2 (55 = Gen 1)= Gen 1)
AA = extended temp (= extended temp (--10 to 85 C)10 to 85 C)
PP = bail latch option = bail latch option
ZZ = = RoHSRoHS compliantcompliant
LLW W AVAGOAVAGO Part Part NumberNumber codingcoding: : AFAFCTCT -- 5757 -- DD 5A5ATTPPZZ
AFAF = = AvagoAvago Fiber OpticsFiber Optics
CTCT = single mode device= single mode device
5757 = SFP (a 59 would be SFF)= SFP (a 59 would be SFF)
DD = 8/4/2G (R would be 4/2/1G)= 8/4/2G (R would be 4/2/1G)
55 = Gen 1 = Gen 1
AA = extended temp (= extended temp (--10 to 85 C)10 to 85 C)
TT == DFB source for 10DFB source for 10--kmkm ((NN is for 30 km device)is for 30 km device)
P P = bail latch option= bail latch option
Z Z = = RoHSRoHS compliantcompliant
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Life time of laser diodes
The lifetime of the laser device can be approximated
by the Arrhenius equation:
A scaling factor (device constant, A 0,95 1)Ea activation energy in [ eV ]
K Boltzmanns constant k =8,6 x 10 -5 eV/K
T temperature [Kelvin]
For 1310 nm = 1,24/Eg [m] Eg = 0,8 eVwe using Ea < Eg 3 eV (for Ge = 0,7- 0,8 eV)
Ea - is the amount of energy which liberate (make free) the
chemical bindings from the semiconductor material.
e10,48
e11,15
e11,5
e12
exp(Ea/kT)
34.476,10 h60 C 333,15 K
67.371 h40 C 313,15 K
95.000 h30 C 303,15 K
156.000 h27 C 300,15 K
t lifetime [hours]Temperature
T K=273,15 + T C
20 30
Hours
Temperature
27 40 60
34.000
67.000
95.000
156.000
For laser diodes which operating at T=40 C the lifetime ist = 67370 h = 7,69 years
For T=22 C the lifetime is about t =170.000 h = 19,4 years
eAtkTEa /=
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LASERLASER Safety Classes (after IEC 60825Safety Classes (after IEC 60825--1 standard)1 standard)
TX Optical Output Power, RX Optical Input Power (average) parameters for AFCT-57R5APZ Avago SFP
(lambda =1310 nm/LW, link range=4 km, type: Avago mini GBIC)
Po Optical output power of the laser -9,5 dBm (minimum) < Po < - 3 dBm (maximum value)
P_in Input optical power (rec. sensibility) -15,37 dBm (minimum) < P_in < - 3 dBm (maximum value)
Remark: x = 10 lg(P) lgP = x/10 P = 10 (x/10) (P-arbitrary power in mW, x dBm decibell milliwatt)For example: -3 dBm P = 10 (-3/10) = 10 (-0,3) = 1/10 0,3 = 1/1,995 = 0,5012 mW < 1 W [ Class 1 ]
Class 1 The resulting laser beam optical power is under the MPE Maximum Permissible Exposure
(This class is not dangerous and not able to produce significant eye trauma.)
Class 2 Low power visible continuous wave lasers with maximum outgoing optical power = 1 mW
Attention: Don't look into the ray of laser-light coming out of optical transceivers.
Class 3a Medium power lasers with outgoing optical power = 5 mW with other restriction (limitation)
which is that: E = d/dA [W/m2] the laser beam radiated surface power 25 W/m2 (laser pointers)
Class 3b Medium power lasers with outgoing optical power = [ 5 mW 500 mW ] continuous wave
They are very hazardous for the eye and can cause blindness. (can burn the retina of the eye)
Class 4 * High power lasers with outgoing optical power > 500 mW (no over limit for the outgoing optical power).
They can produce eye or skin trauma and they are flammable.
Laser Radiation
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